Disturbances in movement coordination are the least well understood but often the most debilitating with respect to functional recovery following stroke. These deficits in coordination are expressed in the form of abnormal muscle synergies and result in limited and stereotypic movement patterns that are functionally disabling. The result of these constraints in muscle synergies is an abnormal coupling between shoulder abduction and elbow flexion, which significantly reduces reaching range of motion or workspace when an individual with stroke lifts the weight of the impaired arm against gravity. In Phase I of this STTR the first prototype of the Arm Coordination Training 3-D system (ACT3D) was developed and tested. It consists of a force controlled robot combined with a Biodex System 3 seating system and a compact LCD visual display. As part of Phase I, it was demonstrated that the ACT3D could be used to completely eliminate the weight of the arm or provide partial support of the limb during active reaching. It was also demonstrated that individuals with chronic stroke can be trained to overcome gravity-induced discoordination subsequently increasing the workspace of the paretic arm. During Phase II of this STTR, the results obtained in Phase I will be expanded upon by developing and building a greatly improved commercial product. The commercial ACT3D system will have an increased motion range, reduced inertial effects as experienced by the individual with stroke, and increased safety features compared with the original prototype (aim 1). Furthermore, it will offer intuitive user- friendly software that conforms to clinical demands (aim 2). Finally, the performance of the commercial system will be tested for an expanded set of training and strengthening tasks that include reaching movements in several planes, in the presence of inertial or viscous loads and under isokinetic or velocity-controlled constraints (aim 3). The performance of the system will be monitored simultaneously for its ease of use, overall safety, perceived inertial effects, and effectiveness of the visual feedback system. The commercial ACT3D system will be designed to provide high-resolution measurements of physiological (strength and coordination) and functional (reaching workspace) performance that can be readily employed in assessing the effectiveness of rehabilitation interventions. Additionally, the commercial ACT3D system will be designed for the implementation of novel rehabilitation interventions that are expected to increase the functional reaching abilities of individuals with stroke. Finally, the envisioned system will be a safe and relatively compact intervention/measurement device that can be easily deployed even in the smallest clinics. The marketing and sales of the proposed ACT3D system (Phase III of this project) will be realized by a consortium consisting of Lam Design Management LLC, Northwestern University, Biodex Medical Systems and Hocoma, Inc. 7. Project Narrative The commercial ACT3D system will be designed to provide high-resolution measurements of physiological (strength and coordination) and functional (reaching workspace) performance that can be readily employed in assessing the effectiveness of rehabilitation interventions. Additionally, the commercial ACT3D system will be designed for the implementation of novel rehabilitation interventions that are expected to increase the functional reaching abilities of individuals with stroke. Finally, the envisioned system will be a safe and relatively compact intervention/measurement device that can be easily deployed even in the smallest clinics. [unreadable] [unreadable]